基于STATCOM和LCC-MTDC技术的大规模风电并网技术研究

以西北电网千万千瓦级风场为背景,提出了采用相控换流器与STATCOM结合的多端直流输电技术进行大规模风电并网的方法。从两个层面上进行控制器的设计,一是从含有STATCOM的整流器交流侧子系统角度,针对策略的快速响应能力以及良好的控制特性。STATCOM非线性特性,引入逆系统方法设计其控制器并推导整流器直流侧电流与STATCOM直流侧电压的关系,提出适合于整流器的控制策略,保证交流侧功率平衡。其次从MTDC整体性能出发,设计相应的控制策略来确保系统稳定运行。在PSCAD/EMTDC中的仿真结果验证了所提控制策略的快速响应能力以及良好的控制特性。

Research on LCC-MTDC and STATCOM technology for wind farms integration

This paper proposes the line-commutated converter based multi-terminal HVDC (LCC-MTDC) combining with the static synchronous compensator (STATCOM) for doubly-fed induction generator (DFIG) based wind farms integration in the context of Northwest Grid (NG) in China. The control strategies design is approached from two aspects. One aims to the AC system on the rectifier side. To coordinate the wind farm, STATCOM and rectifier, the inverse system method is introduced to design the controller in view of the nonlinear characteristic of STATCOM. Meanwhile, the control strategy for the rectifier is proposed to balance the active power in the subsystem and ensure the DC link voltage of STATCOM constant. On the other hand, the single-point voltage control strategy suitable for LCC-MTDC is conceived to guarantee the stable operation of the system by considering the control characteristics of both rectifiers and inverters. Simulations carried out in PSCAD/EMTDC have proven that the proposed control strategies possess favorable control performance and fast response speed.